CVE-2026-89913 KVM: arm64: vgic-v3: take an LPI reference in vgic_v3_save_pending_tables
A race condition in the Linux kernel's KVM arm64 VGIC implementation allows a use-after-free, potentially leading to code execution or privilege escalation.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-89913?
CVE-2026-89913 is a high-severity use after free vulnerability in Linux, published on 16 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
KVM: arm64: vgic-v3: take an LPI reference in vgic_v3_save_pending_tables
vgic_v3_save_pending_tables() iterates dist->lpi_xa using xa_for_each() and dereferences the returned struct vgic_irq in the loop body without holding a reference on the LPI.
The xarray iterator only provides temporary RCU coverage while looking up the current entry. That is not sufficient for this loop body, which reads fields from struct vgic_irq and performs guest memory accesses before the iteration completes.
A concurrent path can trigger this race: the irqfd cached injection path (vgic_its_inject_cached_translation) obtains a transient LPI reference via vgic_its_check_cache() without holding kvm->lock, vcpu->mutex, config_lock, or its_lock. If guest ITS DISCARD then drops the cache and ITE references under its_lock, the transient inject reference may become the final one. When vgic_put_irq() drops it, the LPI is erased from lpi_xa and freed via kfree_rcu(). Meanwhile, vgic_v3_save_pending_tables() may still hold a stale pointer obtained from the xarray iterator and dereference it after the RCU grace period completes.
Fix this by re-fetching each iterated LPI via vgic_get_irq(), which takes a stable reference, and dropping it with vgic_put_irq() on all paths. This matches the pattern already used by other lpi_xa iterators in the vgic ITS code.
Which versions are affected by CVE-2026-89913?
How do I fix CVE-2026-89913?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-89913 being exploited?
There is no known exploitation of CVE-2026-89913 in the wild and no public exploit code.
Sources
Also known as AZL-101282, BELL-CVE-2026-89913, DEBIAN-CVE-2026-89913, GHSA-x7mw-48gf-2rxm, UBUNTU-CVE-2026-89913.